libzint.so: suppress exporting INTERNAL functions to the shared library; ZINT_TEST

backend/tests/testcommon.h

@@ -37,9 +37,7 @@
 #define TESTCOMMON_H
 
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <zint.h>
 #include "../common.h"
 
 extern int assertionFailed;